Bailey was on the schedule to pitch against the Rays Saturday and did not.

Valentine claimed not to know how Bailey became injured, speculating that it happened when he pitched against the Blue Jays March 25. The manager said he did not know about the injury until Friday.

“I’m not sure how likely it is,’’ Valentine said when asked if Bailey would be placed on the disabled list. “But he hasn’t pitched in a while.’’

The Sox took a gamble when they acquired the oft-injured Bailey from the Athletics in December to replace Jonathan Papelbon as closer.

Bailey strained his forearm in spring training last season and did not come off the disabled list until May 29.

Bailey had an elbow procedure in September of 2010 and offseason knee surgery in 2009. He did not appear in a game this spring until March 12 because of a strained lat muscle behind his shoulder.

Bailey appeared in 68 games for Oakland in 2009, winning the American League Rookie of the Year award and making the All-Star Game. That dropped to 47 games in 2010 and 42 games in 2011.

Because Bailey has not pitched in a major league game since March 25, he could be placed on the 15-day DL retroactively to March 26. That would make him eligible to return April 10. He would have missed only four regular-season games at that point.

“That was a really good coincidence,’’ Valentine said.

Before the injury, Bailey was on pace to be ready for the season, having thrown 7 2/3 innings with time to get in two more before camp broke. He went 1 2/3 innings in the minor league game Wednesday, throwing 26 pitches and striking out three.

According to Valentine, Bailey pitched with the thumb injury that day.

“His legs were underneath him,’’ Valentine said. “If this all checks out it shouldn’t take too much to get him back in the saddle.’’

If Bailey does go to the disabled list, the Red Sox will look to Alfredo Aceves and Mark Melancon as their late-inning relievers.

“Good options, and I think that things have been done accordingly to make sure that we’re covered there,’’ Valentine said.

By that, Valentine is referring to the decision to use Aceves in relief after he was tried as a starter in spring training. Aceves learned he was going back to the bullpen Sunday morning.

“I like to be a dream maker, not a dream breaker,’’ Valentine said. “He wasn’t happy about it, obviously. I told him he has a very, very important role on this team. I think he’s one of the best pitchers in camp and trying to figure out where it is we need him the most is a very difficult, perplexing problem.

“I could see him pitching at the end of the game very easily. When we look at the situation with this team, it seems he has incredible value, not being locked down one day [as a starter].’’

Aceves has four career saves and a 2.62 earned run average in 105 career relief appearances.

Melancon became Houston’s closer last season, recording 20 saves. He had a 2.78 ERA and averaged 8.0 strikeouts per nine innings.

Cherington said when the Red Sox traded for Melancon that he was capable of being used as a closer.

“With [Bailey] there’s got to be a plan for when he can’t go,’’ Valentine said. “So now it’s that plan plus somebody else. This has all been happening quickly and we’ve had a lot of meetings today. I haven’t formulated everything in my mind and I don’t know that I have to.

“It seems that it’s OK. It seems to me that with Aceves being a very key component three days ago, he’s even more of a key component now.’’

Valentine said the Red Sox might start the season carrying eight relief pitchers instead of the usual seven to increase their flexibility. Scott Atchison, Michael Bowden, and Justin Thomas were expecting to learn whether they made the team Sunday. Now that decision has been delayed.

“As weird as it is to a lot of the players on the team, which is the last thing I ever want to do is make it any less comfortable than it has to be, I think everybody understands the situation,’’ Valentine said.